Thanks both
This is a simpl? Boat application. The USB input is from a chart plotter interface which sends data to PCs etc. I can get the format of all possible records, but they are all simple records streaming out sequentially. The marine standard is NMEA.

I'll take a look at small talk.

I want to write a simple application to read a data stream from a USB input, select some record types and output to an Rs232 output. Which is the best programming language please? Any sample programmes welcome.
Thanks

I have a new Pi3, Rii keyboard and they don't connect.
I just get the error Pairing failed GDBus.Error.org.bluez.Error.ConnectionAttemptFailed.Page Timeout

Help please?